Mechanization of arrow root processing

Producing starch and flour from arrowroot tubers is laborious, time-consuming, and low-end product recovery. Mechanizing some aspects in the manual method will improve the processing system. Traditional processing of arrowroot involves washing of rhizomes and careful peeling of skin; rewashing of peeled rhizomes and careful peeling of skin; rewashing of peeled rhizomes; grating to produce coarse pulp; mixing of the pulp with clean water; series of sieving to separate the fiber; allowing the liquid to stand and let the starch out; removing the starch, mixing it with more water; and resettling overnight. Malinis et al. (BU), in cooperation with a private manufacturer, KOLBI, mechanized the washing, rasping, juice extraction, drying, and milling of the processing system through a 2-year project (2003- 2005) conducted in Albay and Marinduque [Philippines]. The researchers evaluated the technical and economic feasibility of the mechanized system. Manual Method. Under the traditional method of processing arrowroot, 120 kg can be processed in an hour, resulting in 9-10% flour recovery; it requires 2-5 days to produce flour during rainy days, with the same flour recovery. Washing by hand takes about 3-5 minutes per kilogram. It takes an hour to crush and rasp 15 kg of rhizomes. Sundrying the collected starch takes 3-5 days. Crushing of dried clumps of starch and sieving manually resulted in 9-11% fine starch recovery and 8% meal recovery. Mechanical Interventions. Testing of mechanical washer for arrowroot showed that the machine can wash 1 t of tubers/hour, with washing efficiency of 98.44%. The granulator, which was used to cut the crop into, small pieces to facilitate juice extraction, increased starch recovery from 12% (without use of granulation) to 16%. The multicrop extruder that performed crushing, juice extraction and milling generated an overall extraction efficiency of 86.9%. Juice extraction was 300 mL/minute, with juice recovery of 51.4%. The KOLBI tray- type dryer had a capacity of 250 kg/batch. Drying temperature ranged from 55 deg C to 65 deg C in 3-5 hours. The dryer was either ricehull fired or LPG-fueled. The multicrop micromill showed an average milling capacity of 40 kg/hour, with a milling efficiency of 98%. Computation of the economics of processing arrowroots showed that the manual process would cost P 6.00/kg excluding drying which was done intermittently. The cost of mechanical operation without using granulator amounted to P 6.05/kg with an ROI of 32%. With granulator, cost of mechanical operation increased to P 6.30/kg, with an ROI of 40%. The development of mechanized technologies for arrowroot processing could increase production of starch, which has several uses in food enterprises and industry. This could provide additional source of income for farmers women, and out-of-school youth.